Multiweld secondary.



E. PULD-A.

MULTIWELD SECONDARY.

APPLICATION FILED H13. 18. 1914.

1,103,041 Patented July 14,1914.

INVENTOR Edward ,Fulda BY Y / ATTORNEYS EDWARD FULDA, or NEW YORK, 1v. Y.

MULTIWELD' SECONDARY.

Specification of Letters Patent.

Application filed February 18, 1914. Serial No. 819,310.

To all whom it may concern Be it known that'l EDWARD FULDA, a citizen of the United States, and a resident of New- York city, in the county of New York and State of New York, have invented certain new and useful Improvements in Multiweld secondaries, of which the following is a specification.

My invention relates to the construction of apparatus for electric welding or other operations in which heating electric current of large volume but low,potential is .passed through the work to bring the same .up to the temperature requisite for the operation.

The object of the invention is to providea construction of apparatus wherein a number of pairs of work-engaging electrodes may all be supplied with current from the same transformer secondary and in such manner that the same heating eifects shall be produced in all the pieces or portions of work with which they engage.

A further object is to secure the maximum efliciency from a multi-weld secondary by reducing-the total length of secondary to the lowest practicable degree, as well as to provide a suitable clearance or opening for the insertion of the work.

To these ends my invention consists in the construction of apparatus more particularly hereinafter described and then specified in the claims.

In the accompanying drawings Figure 1 is a side elevation of one form of apparatus in which my invention may be embodied. Fig. 2 shows for comparison a preyious construction of multi-weld secondary. Fig. 3 shows my invention as carried out in a structure wherein two or more primaries act upon the secondary casting to produce electromotive forces acting 1n series or tending to reinforce one another so as to produce an increased potential across the transformer terminal bars.

Referring to Fig. 1, the copper casting or heavy mass of copper forming the secondary of the metal working transformer is indicated at 1. Said copper mass or casting may be of any form desired and may have a primary 2 and a laminated iron core 3 disposed with relation to the secondary and to one another in any of'the ways ordinarily practised in the art.

4, 4 indicates a pair of heavy copper bars forming terminal bars of the secondary and united with the casting 1, integrally or otherwise. The said terminal bars 4, 4 extend, as shown, in opposite directions from the casting 1, but parallel to one another, as shown, leaving a gap between them for the insertion of the work when the appara tusis employ-ed as a multi-weld apparatus and the heating and pressure is produced by pairs of work-engaging electrodes arranged in said gap.

Two or more pairs of work engaging electrodes are indicated at 5, 5. Any number of pairs may be employed, five being the number shown. These electrodes are of any proper r desired form or shape to engage the pieces of'work or portions of the same piece and to supply heating current thereto in the manner well understood in the art. One member 5 of each pair may be fixed and the other member 5 movable, the members 5 being moved together or separately, as choice may dictate and the character of work to be performed may demand. Said electrodes are merely shown as typical of any form or shape of construction of 'workengaging electrodes employed for electrical welding or metal working operations.

By arranging the terminal bars 4, 4' as shown and so that they extend in opposite directions, as indicated, the difference of potential across any pair of electrodes 5, 5 will be the sameas that of all other pairs since, as will be obvious, any drop of potential in one member of a pair due to its greater distance from the point or portion of the secondary from which the bar 4 extends, will be compensated for by the lesser drop of potential of its opposite or complementary member 5 which, as will be seen, is correspondingly nearer to the portion or part of the secondary circuit from which the terminal bar 4 extends. The result is that the same difference of potential exists across all the pairs with a corresponding uniformity of heating current through all the welds or portions of work to be heated.

This effect is made apparent by comparison with aprevious construction, such as illustrated in Fig. 2, in which the terminal bars extendin the same direction and one of them, as for instance. 4, forms the terminal of a secondary circuit which is partially returned upon itself. In such construction a difference of potential across the electrodes at the extreme end of the terminal bars will be less than that of the pair at the other Patented July 14, 1914.

extremity of the set of four pair owing to thedrop in potential along the bars.

The construction forming my invention and illustrated in Fig. 1, hasthe further advantage that the length of the secondary circuit for a multi-weld or multi-electrode transformer may bemuch shorter than the one of the form shown in, Fig. 2, thereby providing an apparatus which will be of higher electrical efficiency.

Referring to Fig. 3, two primaries or vsets of primary coils 2, 2 are shown, said coils acting upon the same secondary bar or casting which terminate in the bars 4:, 4: in a manner to give an increased potential across the bars due to the fact that the electromotive forces set up in the secondary by the primary act in series or to reinforce one another. In this instance two laminated cores 3, 3 may be employed, its own primary 2, 2 cated or in any other suitable way, understood in the art.

I have shown my invention as carried out in an apparatus wherein the electrodes are of that particular type or arranged in relation to one another in that particular way which permits the use of .the apparatus for. welding sheet metal by compressing the sheets or pieces between electrodes which supply the current and also apply the pressure but, as will be understood from the foregoing description, my invention is not limited to that particular type of machine in the manner indias well each associated with but may be used generally for electric welding or metal working apparatus and irrespective of the particular construction of the means for operating upon the heated work after it has been heated to the desired degree by the current passed through it from the work-engaging electrodes of the form chosen with reference to the particular kind of work to be done.

What I claim as my invention is 1. In a multi-electrode electric metal working apparatus, a pair of transformer secondary terminal bars extended parallel to one another but in opposite directions and having two or more pairs of work-engaging electrodes as and for the purpose described.

2. In a multi-electrode electric metal working apparatus, a pair of transformer terminal bars extended parallel to one another but in opposite directions, combined with two or more primary coils acting on the secondary to produce electromotive forces acting in series or tending to reinforce one another so as to produce an increased potential across the transformer terminal bars.

Signed at New York city, in the county of New York and State of New York, this 17th day of February, A. D. 19M.

EDWARD FULDA.

\Vitnesses: I

i W; R. WARNER,

O..T. Trscnnnn, Jr. 

